CN105471284A - power conversion device and over-power protection method thereof - Google Patents
power conversion device and over-power protection method thereof Download PDFInfo
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- CN105471284A CN105471284A CN201410604437.6A CN201410604437A CN105471284A CN 105471284 A CN105471284 A CN 105471284A CN 201410604437 A CN201410604437 A CN 201410604437A CN 105471284 A CN105471284 A CN 105471284A
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- 238000006243 chemical reaction Methods 0.000 title abstract description 9
- 238000001514 detection method Methods 0.000 claims abstract description 18
- 230000008030 elimination Effects 0.000 claims description 66
- 238000003379 elimination reaction Methods 0.000 claims description 66
- 238000009434 installation Methods 0.000 claims description 27
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
- H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
- Protection Of Static Devices (AREA)
Abstract
The invention provides a power conversion device and an over-power protection method thereof. Counting the times that the detection voltage is greater than the first reference voltage and the times that the detection voltage is greater than the second reference voltage to obtain a first count value and a second count value, wherein the detection voltage is a voltage of a current flowing through the power switch and reflecting on a resistor. And when the first count value is greater than or equal to the first threshold value or the second count value is greater than or equal to the second threshold value, stopping switching the power switch. The invention provides a power conversion device and an over-power protection method thereof, which can provide effective over-power protection and prevent the power conversion device or an electronic device using the power conversion device from being damaged due to the fact that the power conversion device continuously generates excessive voltage or current.
Description
Technical field
The invention relates to a kind of electronic installation, and relate to a kind of power supply change-over device and overpower protection method thereof especially.
Background technology
In the prior art, the purposes that power supply change-over device (powerconversionapparatus) is main is the high pressure that Utilities Electric Co. provided and the AC-input voltage (ACinputvoltage) of low stability converts the low pressure and stability preferably VD (DCoutputvoltage) that applicable various electronic installation (electronicdevice) uses to.Therefore, power supply change-over device is widely used in the electronic installations such as computer, office automation devices, industrial control equipment and communication equipment.
But, when there is the situation of open circuit or short circuit in the output of power supply change-over device, likely will can cause the big current of power supply change-over device output abnormality constantly, and make the exception of power supply change-over device itself or the inner component temperature of load increase, thus increase the risk that power supply change-over device itself or the inner element of load damage.
Summary of the invention
The invention provides a kind of power supply change-over device and overpower protection method thereof; effective overpower protection can be provided, avoid power supply change-over device or use the electronic installation of power supply change-over device to be damaged because power supply change-over device produces excessive voltage or electric current constantly.
Power supply change-over device of the present invention, comprises transformer, power switch, resistance, pulse width modulation controlled unit, frequency elimination unit, the first comparing unit, the second comparing unit, the first counting unit and the second counting unit.Wherein transformer has primary side and secondary side, and wherein the first end of primary side is in order to receive input voltage, and secondary side is then in order to provide output voltage to electronic installation.The first end of power switch couples the second end of primary side, and the second end of power switch is coupled to first node, and the control end of power switch receives pulse-width signal.Resistance is coupled between first node and earthed voltage.Pulse width modulation controlled unit, couples the control end of power switch, produces the pulse-width signal of power switched switch.Frequency elimination unit couples pulse width modulation controlled unit, frequency elimination pulse-width signal, to produce the first frequency elimination signal and the second frequency elimination signal.The power end of the first comparing unit couples the first frequency elimination signal, and the first comparing unit compares voltage and first reference voltage of the first node that its input receives, to export the first comparison signal.The power end of the second comparing unit couples the second frequency elimination signal, and the second comparing unit compares voltage and second reference voltage of the first node that its input receives, to export the first comparison signal.First counting unit is coupled between the output of the first comparing unit and pulse width modulation controlled unit, voltage according to the first comparison signal counting first node is greater than the number of times of the first reference voltage, when the number of times that the voltage of first node is greater than the first reference voltage is more than or equal to the first threshold value, forbidden energy pulse width modulation controlled unit.Second counting unit is coupled between the output of the second comparing unit and pulse width modulation controlled unit, voltage according to the second comparison signal counting first node is greater than the number of times of the second reference voltage, when the number of times that the voltage of first node is greater than the second reference voltage is more than or equal to the second threshold value, forbidden energy pulse width modulation controlled unit.
In one embodiment of this invention, at the first comparing unit by the first frequency elimination signal enable period, if the voltage of first node is not greater than the first reference voltage, first comparing unit resets the count value of the first counting unit, at the first comparing unit by the first frequency elimination signal enable period, if the voltage of first node is not greater than the second reference voltage, the second comparing unit resets the count value of the first counting unit.
In one embodiment of this invention, the first above-mentioned reference voltage is greater than the second reference voltage, and the first threshold value is less than the second threshold value.
In one embodiment of this invention, above-mentioned power supply change-over device, also comprises the 3rd comparing unit, in order to compare voltage and the 3rd reference voltage of the first node that its input receives, when the voltage of first node is greater than the 3rd reference voltage, forbidden energy pulse width modulation controlled unit.
In one embodiment of this invention, above-mentioned power supply change-over device, also comprises feedback unit and the 4th comparing unit.Feedback unit couples secondary side, in order to receive output voltage, and output feedback signal according to this.4th comparing unit couples feedback unit, compares voltage and the 4th reference voltage of feedback signal, when the voltage of feedback signal is higher than the 4th reference voltage, and forbidden energy pulse width modulation controlled unit.
The overpower protection method of power supply change-over device of the present invention, comprises the following steps.Pulse-width signal is produced according to the load condition of electronic installation.According to the power switch in pulse-width signal Switching power conversion equipment, provide output voltage to electronic installation to make power supply change-over device.Frequency elimination pulse-width signal, to produce the first frequency elimination signal and the second frequency elimination signal respectively.Judge during the high-voltage level of the first frequency elimination signal detect voltage whether be greater than the first reference voltage, wherein detect voltage be flow through power switch current response at ohmically voltage.During the high-voltage level of the second frequency elimination signal, judge whether detect voltage is greater than the second reference voltage.If detect voltage to be greater than the first reference voltage, count detection voltage is greater than the number of times of the first reference voltage, to obtain the first count value.If detect voltage to be greater than the second reference voltage, count detection voltage is greater than the number of times of the second reference voltage, to obtain the second count value.Judge whether the first count value is more than or equal to the first threshold value and whether the second count value is more than or equal to the second threshold value.If the first count value is more than or equal to the first threshold value or the second count value is more than or equal to the second threshold value, stop power switched switch.
In one embodiment of this invention, if detect voltage not to be greater than the first reference voltage, reset the first count value, if detect voltage not to be greater than the second reference voltage, reset the second count value.
In one embodiment of this invention, the first above-mentioned reference voltage is greater than the second reference voltage, and the first threshold value is less than the second threshold value.
In one embodiment of this invention, the overpower protection method of above-mentioned power supply change-over device, also comprises, and judges that whether detect voltage is greater than the 3rd reference voltage, if detect voltage to be greater than the 3rd reference voltage, stops power switched switch.
In one embodiment of this invention, the overpower protection method of above-mentioned power supply change-over device, also comprises the following steps.Feedback signal is produced according to output voltage.Judge whether the voltage of feedback signal is greater than the 4th reference voltage, if the voltage of feedback signal is higher than the 4th reference voltage, stop power switched switch.
Based on above-mentioned, embodiments of the invention count detection voltage is greater than the number of times of the first reference voltage and detects voltage and be greater than the number of times of the second reference voltage, to obtain the first count value and the second count value, and when the first count value is more than or equal to the first threshold value or the second count value is more than or equal to the second threshold value, stop power switched switch, wherein detect voltage be flow through power switch current response at an ohmically voltage.So set different threshold values for different reference voltages; power switched switch can be stopped ahead of time further according to detecting the situation that voltage exceedes rated voltage; to avoid power supply change-over device or to use the electronic installation of power supply change-over device to be damaged because power supply change-over device produces excessive voltage or electric current constantly, and provide effective overpower protection.
For above-mentioned feature and advantage of the present invention can be become apparent, special embodiment below, and coordinate accompanying drawing to be described in detail below.
Accompanying drawing explanation
Fig. 1 illustrates the schematic diagram of the power supply change-over device of one embodiment of the invention;
Fig. 2 illustrates the waveform schematic diagram of the voltage on the pulse-width signal of one embodiment of the invention, frequency elimination signal and node N1;
Fig. 3 illustrates the waveform schematic diagram of the voltage on the pulse-width signal of another embodiment of the present invention, frequency elimination signal and node N1;
Fig. 4 illustrates the waveform schematic diagram of the voltage on the pulse-width signal of another embodiment of the present invention, frequency elimination signal and node N1;
Fig. 5 illustrates the schematic diagram of the power supply change-over device of another embodiment of the present invention;
Fig. 6 illustrates the overpower protection method flow schematic diagram of the power supply change-over device of one embodiment of the invention;
Fig. 7 illustrates the overpower protection method flow schematic diagram of the power supply change-over device of another embodiment of the present invention.
Description of reference numerals:
102: pulse width modulation controlled unit;
104,106,502,504: comparing unit;
108,110: counting unit;
112: feedback unit;
114: frequency elimination unit;
T: transformer;
Q: power switch;
Rs: resistance;
D: diode;
C: electric capacity;
P: primary side;
S: secondary side;
Vin: input voltage;
Vout: output voltage;
LD: electronic installation;
Vfb: feedback signal;
N1: node;
VPWM: pulse-width signal;
F1, f2: frequency elimination signal;
Vcs: the voltage on node N1;
Vth1, Vth2, Vth3, Vth4: reference voltage;
Ip: electric current;
Vc1, Vc2: comparison signal;
S602 ~ S622, S702 ~ S706: the overpower protection method step of power supply change-over device.
Embodiment
Fig. 1 illustrates the schematic diagram of the power supply change-over device of one embodiment of the invention, please refer to Fig. 1.Power supply change-over device comprises transformer T, power switch Q, resistance Rs, pulse width modulation controlled unit 102, comparing unit 104, comparing unit 106, counting unit 108, counting unit 110, feedback unit 112, frequency elimination unit 114, diode D and electric capacity C.In the present embodiment, transformer T has primary side (primaryside) P and secondary side (secondaryside) S, and the first end of the primary side P of transformer T is in order to receive input voltage vin, the secondary side S of transformer T is then in order to provide output voltage Vout to electronic installation LD.
Wherein, input voltage vin is that AC-input voltage is via the DC input voitage produced after rectifier rectification, input voltage vin received by the primary side P reaction of transformer T is after the voltage of the secondary side S of transformer T, (determined by the coil ratio (turnratio) of first and second side P and the S of transformer T) again via the rectification (rectification) of diode D and the filtering (filter) of electric capacity C, and converts direct current (DC) output voltage Vout required when electronic installation LD operates to.The anode (anode) of diode D couples the first end of the secondary side S of transformer T, and the negative electrode (cathode) of diode D is then coupled to electronic installation LD.In addition, the first end of electric capacity C couples the negative electrode of diode D, and second end of electric capacity C is then coupled to the second end and the earthed voltage of the secondary side S of transformer T.
Feedback unit 112 couples the secondary side S of transformer T, in order to receive VD Vout, and exports the feedback signal Vfb being associated with the load condition (loadingstatus) of electronic installation LD according to this.It should be noted that, as long as any circuit form that can export the feedback signal of the load condition being associated with electronic installation LD can as the feedback unit 112 of the present embodiment, such as utilize the feedback circuit of resitstance voltage divider collocation optical coupler, the enforcement aspect of feedback unit 112 is not as limit.Pulse width modulation controlled unit 102 couples control end and the node N1 of power switch Q, produces pulse-width signal VPWM in order to the feedback signal Vfb exported according to feedback unit 112.The first end of power switch Q (being such as N-type transistor) couples second end of the primary side P of transformer T, and second end of power switch Q is coupled to node N1, and the control end of power switch Q then receives pulse-width signal VPWM.Resistance Rs is coupled between node N1 and earthed voltage.
Frequency elimination unit 114 couples pulse width modulation controlled unit 102, comparing unit 104 and comparing unit 106, and the pulse-width signal VPWM in order to export pulse width modulation controlled unit 102 carries out frequency elimination and produces frequency elimination signal f1 and frequency elimination signal f2.Voltage Vcs on the input receiving node N1 of comparing unit 104 and reference voltage Vth1, voltage Vcs on the input receiving node N1 of comparing unit 106 and reference voltage Vth2, in addition, comparing unit 104 and the power end of comparing unit 106 then receive frequency elimination signal f1 from frequency elimination unit 114 and frequency elimination signal f2 respectively.Counting unit 108 is coupled between the output of comparing unit 104 and pulse width modulation controlled unit 102, and counting unit 110 is coupled between the output of comparing unit 106 and pulse width modulation controlled unit 102.As shown in the waveform schematic diagram of the voltage Vcs on pulse-width signal VPWM, frequency elimination signal f1, f2 of Fig. 2 and node N1, the frequency of frequency elimination signal f1, f2 is 1/2 of pulse-width signal VPWM in the present embodiment, and when frequency elimination signal f1 is high-voltage level, frequency elimination signal f2 is low voltage level.
When frequency elimination signal f1 transfers high-voltage level to, comparing unit 104 will be enabled and carry out voltage Vcs with the voltage swing of reference voltage Vth1 and compare, and exports comparison signal Vc1 according to comparative result.Wherein when voltage Vcs is greater than reference voltage Vth1, count value is increased by 1 according to comparison signal Vc1 by counting unit 108, to count the number of times that voltage Vcs is greater than reference voltage Vth1, when counting unit 108 the count value that adds up be more than or equal to the first threshold value time, represent power supply change-over device and continue the excessive output voltage Vout of one section of Preset Time generation magnitude of voltage, now counting unit 108 is by forbidden energy pulse width modulation controlled unit 102, to stop power switched switch Q, reduce the electric current I p flowing through the primary side of transformer T, power supply change-over device is avoided to continue to produce excessive output voltage Vout, and cause the damage of power switch Q and/or electronic installation LD/burn.In addition, when the voltage Vcs on node N1 is not greater than reference voltage Vth1, represent power supply change-over device without the situation producing excessive output voltage Vout, now counting unit 108 resets count value by according to the comparison signal Vc1 from comparing unit 104.
Fig. 2 illustrates the waveform schematic diagram of the voltage on the pulse-width signal of one embodiment of the invention, frequency elimination signal and node N1, as shown in Figure 2, in Fig. 2 embodiment, numerical value under the waveform of the voltage Vcs on node N1 is the count value of counting unit 108, when the voltage level of the voltage Vcs on node N1 is lower than reference voltage Vth1, it is 0 that the count value of counting unit 108 is reset.And afterwards when the voltage level of the voltage Vcs on node N1 is got back to higher than reference voltage Vth1, counting unit 108 is by stored count value again.When count value is more than or equal to the first threshold value, (threshold value is 100 in the present embodiment, so not as limit) time, pulse width modulation controlled unit 102 is counted unit 108 forbidden energy, and stops output pulse width modulation signal VPWM, also namely stops power switched switch Q.It should be noted that, in some embodiments, also the voltage level of the voltage Vcs on node N1 can be compared repeatedly continuously lower than (such as continuous three times) during reference voltage Vth1 at comparing unit 104, just the count value of counting unit 108 being reset is 0, to avoid count value to be reset because of noise jamming, and cause delaying the time point stopping power switched switch Q.
Similarly, when frequency elimination signal f2 transfers high-voltage level to, the voltage Vcs that comparing unit 106 will be enabled and carry out on node N1 compares with the voltage swing of reference voltage Vth2, and exports comparison signal Vc2 according to comparative result.Wherein when the voltage Vcs on node N1 is greater than reference voltage Vth2, count value is increased by 1 according to comparison signal Vc2 by counting unit 110, the number of times of reference voltage Vth2 is greater than with the voltage Vcs on count nodes N1, when counting unit 110 the count value that adds up be more than or equal to the second threshold value time, represent power supply change-over device and continue for some time the excessive output voltage Vout of generation magnitude of voltage, now counting unit 110 is by forbidden energy pulse width modulation controlled unit 102, to stop power switched switch Q.In addition, when the voltage Vcs on node N1 is not greater than reference voltage Vth2, represent power supply change-over device without the situation producing excessive output voltage Vout, now counting unit 110 resets count value by according to the comparison signal Vc2 from comparing unit 106.In the embodiment of fig. 2, because the voltage Vcs on the node N1 of the embodiment of Fig. 2 is all less than reference voltage Vth2, therefore the count value of counting unit 110 is continuously 0.
It should be noted that in the present embodiment, the voltage level of reference voltage Vth2 is greater than the voltage level of reference voltage Vth1, and the first threshold value is less than the second threshold value.When power supply change-over device produces excessive output voltage Vout, and make voltage Vcs on node N1 except higher than except reference voltage Vth1, time also higher than reference voltage Vth2, the output voltage Vout produced due to power supply change-over device is larger, faster by what make power supply change-over device itself or the inner component temperature of load rise, for avoiding causing the damage of power switch Q and/or electronic installation LD/burn, must forbidden energy pulse width modulation controlled unit 102 as soon as possible, to stop power switched switch Q, therefore the second threshold value is set to and is less than the first threshold value.For example, Fig. 3 illustrates the waveform schematic diagram of the voltage on the pulse-width signal of another embodiment of the present invention, frequency elimination signal and node N1, as shown in the waveform schematic diagram of the voltage Vcs on pulse-width signal VPWM, frequency elimination signal f1, f2 of Fig. 3 and node N1, in Fig. 3 embodiment, numerical value under the waveform of voltage Vcs is the count value of counting unit 110, suppose that the first threshold value is set to 100, and the second threshold value is set to 50.When voltage Vcs on node N1 is greater than reference voltage Vth1 and reference voltage Vth2, the count value of counting unit 110 will want a Zao step to be more than or equal to threshold value than the count value of counting unit 108, also namely the count value of counting unit 110 first will arrive 50, and can forbidden energy pulse width modulation controlled unit 102 as soon as possible, to stop power switched switch Q.
By setting different reference voltages and corresponding threshold value except degree that the output voltage Vout that can produce according to power supply change-over device exceedes rated output voltage determines whether that early a step stops power switched switch Q, the Error Tolerance judging whether stopping power switched switch Q also can be increased.Such as during comparing unit 104 is not enable by frequency elimination signal f1, when the noise that electronic installation LD causes makes voltage Vcs on node N1 sporadicly lower than reference voltage Vth1, because the voltage Vcs on node N1 and reference voltage Vth1 does not compare by comparing unit 104, therefore counting unit 108 can not be reset, and causes delaying the time point stopping power switched switch Q.
In addition; when the load variations of the output of power supply change-over device causes the magnitude of voltage of the voltage Vcs on node N1 to occur periodic size variation; the power supply change-over device of the present embodiment also can stop power switched switch Q, to protect power switch Q and/or electronic installation LD.Fig. 4 illustrates the pulse-width signal of another embodiment of the present invention, the waveform schematic diagram of the voltage on frequency elimination signal and node N1, for example, as the pulse-width signal VPWM of Fig. 4, frequency elimination signal f1, shown in the waveform schematic diagram of the voltage Vcs on f2 and node N1, the magnitude of voltage size of the voltage Vcs on node N1 periodically becomes and diminishes greatly, so due to the magnitude of voltage of the voltage Vcs on node N1 be greater than reference voltage Vth1 during be comparing unit 104 enable by frequency elimination signal f1 during, and the magnitude of voltage of voltage Vcs on node N1 is not during to be comparing unit 104 during being less than reference voltage Vth1 enable by frequency elimination signal f1, therefore the count value of counting unit 108 still can add up unceasingly, and can not be reset because the magnitude of voltage of voltage Vcs is less than reference voltage Vth1, prohibit and cause power supply change-over device cannot stop power switched switch Q, cause the damage of power switch Q and/or electronic installation LD.
Though above-described embodiment is described with two counting units 108,110 of two comparing units 104,106 and correspondence, the number of right comparing unit and counting unit is not as limit, power supply change-over device can comprise more comparing unit and counting unit in other embodiments, also namely voltage Vcs can compare from more how different reference voltages, and the reference voltage that wherein magnitude of voltage is higher will correspond to lower threshold value.The situation that power supply change-over device so can be made to grasp voltage Vout more accurately exceed assigned voltage, and then stop power switched switch Q on the most appropriate opportunity, be damaged to prevent power switch Q and/or electronic installation LD.
Fig. 5 illustrates the schematic diagram of the power supply change-over device of another embodiment of the present invention, please refer to Fig. 5.The power supply change-over device of the present embodiment also comprises comparing unit 502 and comparing unit 504 compared to the power supply change-over device of Fig. 1 embodiment.Voltage Vcs on the input receiving node N1 of wherein comparing unit 502 and reference voltage Vth3, the output of comparing unit 502 then couples pulse width modulation controlled unit 102, the input receiving feedback signals Vfb of comparing unit 504 and reference voltage Vth4, the output of comparing unit 504 then couples pulse width modulation controlled unit 102.When the comparative result of comparing unit 502 be voltage Vcs on node N1 be greater than reference voltage Vth3 time, comparing unit 502 just direct forbidden energy pulse width modulation controlled unit 102, to stop power switched switch Q.Due to comparing unit 502 once the voltage Vcs compared on node N1 be greater than reference voltage Vth3 namely can forbidden energy pulse width modulation controlled unit 102; also namely reference voltage Vth3 is very high voltage concerning power supply change-over device; for available protecting power supply change-over device; must close power switch Q immediately, therefore the magnitude of voltage of reference voltage Vth3 will be greater than above-mentioned reference voltage Vth1 and reference voltage Vth2.Similarly, if the voltage that comparing unit 504 compares feedback signal Vfb is greater than reference voltage Vth4, comparing unit 504 also can direct forbidden energy pulse width modulation controlled unit 102, to stop power switched switch Q.
Fig. 6 illustrates the overpower protection method flow schematic diagram of the power supply change-over device of one embodiment of the invention, please refer to Fig. 6.From the description of the power supply change-over device described in above-described embodiment, the overpower protection method of power supply change-over device can comprise the following steps.First, pulse-width signal (step S602) is produced according to the load condition of electronic installation.Then, according to the power switch in pulse-width signal Switching power conversion equipment, to make power supply change-over device provide output voltage to electronic installation (step S604), wherein power switch can such as be implemented by N-type transistor.Then, frequency elimination pulse-width signal, to produce the first frequency elimination signal and the second frequency elimination signal (step S606) respectively.During the high-voltage level of the first frequency elimination signal, judge whether detect voltage is greater than the first reference voltage (step S608) afterwards again, in addition and judge during the high-voltage level of the second frequency elimination signal detect voltage whether be greater than the second reference voltage (step S610), wherein detect voltage be flow through power switch current response at ohmically voltage.If wherein detect voltage to be greater than the first reference voltage during the high-voltage level of the first frequency elimination signal, count detection voltage is greater than the number of times of the first reference voltage, to obtain the first count value (step S612), on the contrary, if detect voltage not to be greater than the first reference voltage during the high-voltage level of the first frequency elimination signal, then reset the first count value (step S614).Similarly, if detect voltage to be greater than the second reference voltage during the high-voltage level of the second frequency elimination signal, count detection voltage is greater than the number of times of the second reference voltage, to obtain the second count value (step S616), if and during the high-voltage level of the second frequency elimination signal, detect voltage be not greater than the second reference voltage, reset the second count value (step S618).Then, in step S612 with after step S616, judge whether the first count value is more than or equal to the first threshold value and whether the second count value is more than or equal to the second threshold value (step S620), wherein the first reference voltage is greater than the second reference voltage, and the first threshold value is less than the second threshold value.If the first count value is more than or equal to the first threshold value or the second count value is more than or equal to the second threshold value, then stop power switched switch (step S622), if and the first count value is not more than or equal to the first threshold value and the second count value is not more than or equal to the second threshold value, then get back to step S602, produce pulse-width signal according to the load condition of electronic installation.
Fig. 7 illustrates the overpower protection method flow schematic diagram of the power supply change-over device of another embodiment of the present invention, please refer to Fig. 7.Compared to the overpower protection method of the power supply change-over device of Fig. 6 embodiment, the present embodiment also comprises step S702 ~ S706.After step S604, the overpower protection method of the power supply change-over device of the present embodiment also produces a feedback signal (step S702) according to output voltage.Then, judge whether be greater than three reference voltage (step S704), wherein the 3rd reference voltage is greater than above-mentioned first reference voltage and the second reference voltage if detecting voltage.If detect voltage to be greater than the 3rd reference voltage, then enter step S622, stop power switched switch.And if detection voltage is not greater than the 3rd reference voltage, then then judge whether the voltage of feedback signal is greater than the 4th reference voltage (step S706), if the voltage of feedback signal higher than the 4th reference voltage, then enters step S622, stop power switched switch.On the contrary, if the voltage of feedback signal is not greater than the 4th reference voltage, then then enter step S606, frequency elimination pulse-width signal, to produce the first frequency elimination signal and the second frequency elimination signal respectively.
In sum, embodiments of the invention count detection voltage is greater than the number of times of the first reference voltage and detects voltage and be greater than the number of times of the second reference voltage, to obtain the first count value and the second count value, and when the first count value is more than or equal to the first threshold value or the second count value is more than or equal to the second threshold value, stop power switched switch, wherein detect voltage be flow through power switch current response at an ohmically voltage.So set different threshold values for different reference voltages; power switched switch can be stopped ahead of time further according to detecting the situation that voltage exceedes rated voltage; to avoid power supply change-over device or to use the electronic installation of power supply change-over device to be damaged because power supply change-over device produces excessive voltage or electric current constantly, and provide effective overpower protection.
Last it is noted that above each embodiment is only in order to illustrate technical scheme of the present invention, be not intended to limit; Although with reference to foregoing embodiments to invention has been detailed description, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein some or all of technical characteristic; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the scope of various embodiments of the present invention technical scheme.
Claims (10)
1. a power supply change-over device, is characterized in that, comprising:
One transformer, has a primary side and a secondary side, and wherein the first end of this primary side is in order to receive an input voltage, and this secondary side is then in order to provide an output voltage to an electronic installation;
One power switch, its first end couples the second end of this primary side, and the second end of this power switch is coupled to a first node, and the control end of this power switch receives a pulse-width signal;
One resistance, is coupled between this first node and an earthed voltage;
One pulse width modulation controlled unit, couples the control end of this power switch, produces the pulse-width signal switching this power switch;
One frequency elimination unit, couples this pulse width modulation controlled unit, this pulse-width signal of frequency elimination, to produce one first frequency elimination signal and one second frequency elimination signal;
One first comparing unit, its power end couples this first frequency elimination signal, and this first comparing unit compares voltage and one first reference voltage of this first node that its input receives, to export one first comparison signal;
One second comparing unit, its power end couples this second frequency elimination signal, and this second comparing unit compares voltage and one second reference voltage of this first node that its input receives, to export one first comparison signal;
One first counting unit, be coupled between the output of this first comparing unit and this pulse width modulation controlled unit, the voltage counting this first node according to this first comparison signal is greater than the number of times of this first reference voltage, when the number of times that the voltage of this first node is greater than this first reference voltage is more than or equal to first threshold value, this pulse width modulation controlled unit of forbidden energy; And
One second counting unit, be coupled between the output of this second comparing unit and this pulse width modulation controlled unit, the voltage counting this first node according to this second comparison signal is greater than the number of times of this second reference voltage, when the number of times that the voltage of this first node is greater than this second reference voltage is more than or equal to second threshold value, this pulse width modulation controlled unit of forbidden energy.
2. power supply change-over device according to claim 1, it is characterized in that, at this first comparing unit by this first frequency elimination signal enable period, if the voltage of this first node is not greater than this first reference voltage, this the first comparing unit resets the count value of this first counting unit, at this first comparing unit by this first frequency elimination signal enable period, if the voltage of this first node is not greater than this second reference voltage, this second comparing unit resets the count value of this first counting unit.
3. power supply change-over device according to claim 1, is characterized in that, this first reference voltage is greater than this second reference voltage, and this first threshold value is less than this second threshold value.
4. power supply change-over device according to claim 1, is characterized in that, also comprises:
One the 3rd comparing unit, compares voltage and one the 3rd reference voltage of this first node that its input receives, when the voltage of this first node is greater than the 3rd reference voltage, and this pulse width modulation controlled unit of forbidden energy.
5. power supply change-over device according to claim 1, is characterized in that, also comprises:
One feedback unit, couples this secondary side, in order to receive this output voltage, and exports a feedback signal according to this; And
One the 4th comparing unit, couples this feedback unit, compares voltage and one the 4th reference voltage of this feedback signal, when the voltage of this feedback signal is higher than the 4th reference voltage, and this pulse width modulation controlled unit of forbidden energy.
6. an overpower protection method for power supply change-over device, is characterized in that, comprising:
A pulse-width signal is produced according to the load condition of an electronic installation;
Switch the power switch in this power supply change-over device according to this pulse-width signal, provide an output voltage to this electronic installation to make this power supply change-over device;
This pulse-width signal of frequency elimination, to produce one first frequency elimination signal and one second frequency elimination signal respectively;
Judge during the high-voltage level of this first frequency elimination signal one detect voltage whether be greater than one first reference voltage, wherein this detection voltage be flow through this power switch current response at an ohmically voltage;
During the high-voltage level of this second frequency elimination signal, judge whether this detection voltage is greater than one second reference voltage;
If detect voltage to be greater than this first reference voltage, count the number of times that this detection voltage is greater than this first reference voltage, to obtain one first count value;
If detect voltage to be greater than this second reference voltage, count the number of times that this detection voltage is greater than this second reference voltage, to obtain one second count value;
Judge whether this first count value is more than or equal to one first threshold value and whether this second count value is more than or equal to one second threshold value; And
If this first count value is more than or equal to this first threshold value or this second count value is more than or equal to this second threshold value, stop switching this power switch.
7. the overpower protection method of power supply change-over device according to claim 6; it is characterized in that, if this detection voltage is not greater than this first reference voltage, reset this first count value; if this detection voltage is not greater than this second reference voltage, reset this second count value.
8. the overpower protection method of power supply change-over device according to claim 6, is characterized in that, this first reference voltage is greater than this second reference voltage, and this first threshold value is less than this second threshold value.
9. the overpower protection method of power supply change-over device according to claim 6, is characterized in that, also comprise:
Judge whether this detection voltage is greater than one the 3rd reference voltage, if this detection voltage is greater than the 3rd reference voltage, stop switching this power switch.
10. the overpower protection method of power supply change-over device according to claim 6, is characterized in that, also comprise:
A feedback signal is produced according to this output voltage; And
Judge whether the voltage of this feedback signal is greater than one the 4th reference voltage, if the voltage of this feedback signal is higher than the 4th reference voltage, stop switching this power switch.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW103134736A TWI542102B (en) | 2014-10-06 | 2014-10-06 | Power conversion apparatus and over power protection method thereof |
| TW103134736 | 2014-10-06 |
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| Publication Number | Publication Date |
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| CN105471284A true CN105471284A (en) | 2016-04-06 |
| CN105471284B CN105471284B (en) | 2018-03-20 |
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| CN201410604437.6A Active CN105471284B (en) | 2014-10-06 | 2014-10-31 | power conversion device and over-power protection method thereof |
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| Country | Link |
|---|---|
| US (1) | US9343977B2 (en) |
| CN (1) | CN105471284B (en) |
| TW (1) | TWI542102B (en) |
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| CN110299694A (en) * | 2018-03-23 | 2019-10-01 | 东莞劲华电子有限公司 | The overpower protection method and device of power supply unit |
| CN112953242A (en) * | 2021-03-25 | 2021-06-11 | 深圳南云微电子有限公司 | Instantaneous overpower control method and circuit |
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| US9654011B2 (en) * | 2015-04-24 | 2017-05-16 | Richtek Technology Corp. | Control circuit and method of a power converter |
| TWI704737B (en) * | 2019-04-17 | 2020-09-11 | 宏碁股份有限公司 | Over power protection circuit, charger and over power protection method |
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Also Published As
| Publication number | Publication date |
|---|---|
| US20160099648A1 (en) | 2016-04-07 |
| TWI542102B (en) | 2016-07-11 |
| TW201614919A (en) | 2016-04-16 |
| US9343977B2 (en) | 2016-05-17 |
| CN105471284B (en) | 2018-03-20 |
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